An underwater cable may terminate at a bulkhead of a subsea installation, at the back end of an underwater connector, or at a harness that provides an intermediate unit between a cable and another cable or subsea installation or connector. In some cable termination assemblies, a seal is formed at the rear of a cable termination chamber housing to seal against the cable jacket. In such cable termination assemblies, the interior of the housing is thereby separated from ambient water to the rear or from oil contained in a hose accommodating the cable. The seal is formed of a relatively hard plastic cone having an aperture through which the cable jacket extends, and a radially inwardly facing surface for sealing against the jacket. The cone has a radially outwardly facing conical surface engaged by a radially inwardly facing conical surface of a seal energizing member. The seal energizing member is urged axially towards the cone member so as to compress it radially inwardly and form a seal with the cable jacket.
Another type of sealing configuration for use in cable termination assemblies provides a seal between axially adjacent chambers into which the cable extends. Each chamber contains a fluid (e.g., oil or gel) and is pressure balanced with respect to outside pressure by having a flexible wall. The outside of the flexible wall is exposed directly or indirectly to the outside environment. In order to separate the fluid in the two chambers, a pair of back-to-back seals is provided. The cable passes through an aperture in a hard plastic seal holder. At each axially opposite side of the seal holder, a first part of a respective elastomeric seal member engages and seals against the cable jacket, and a second part of the seal member engages and seals against an axial extension of the seal holder.